This invention relates generally to a fiber optic network. More particularly the invention relates to a fiber channel jumper that may connect two fiber optic system common wavelength fibers or may be used to add or drop common wavelengths into open fiber connections.
In telecom, video transport systems and other fiber optic network applications, it is desirable for a fiber optic OAD (Optical Add Drop) product to have low fiber optic insertion loss and some form of electrical monitoring of individual wavelength channels within an OAD network system element. Typically, an OAD is basically two wavelength division multiplexing (WDM) devices capable of multiplexing and de-multiplexing multiple channels or wavelengths of light. Typically, a plurality of individual fibers are provided wherein each individual fiber communicates a particular wavelength or channel of light and another individual fiber communicates a polychromatic light signal comprising the particular wavelengths communicated by the plurality of individual fibers. A major function of the OAD is to pass thru or express selected individual fiber channels connected to an OAD system element. Expressing is therefore accomplished by selectively placing jumpers between the mux/demux and demux/mux devices within the OAD.
Conventional OAD systems utilize optical jumpers that have high insertion loss, which may exceed 1-3 dB. Typical connectors that have been used may be generally classified into five major categories, including resilient ferrule, rigid ferrule, grooved plate hybrids, expanded beam and rotary.
Desirable attributes of a jumper component include ease of installation and the ability to provide low optical power loss with a single mode fiber optic cable. One type of typical related art fiber optic jumpers is a jumper having a xe2x80x9cduplexxe2x80x9d configuration. A disadvantage and problem of a xe2x80x9cduplexxe2x80x9d configuration is that such a configuration imposes a tight bend radius on single mode fibers. The tight bend radius creates excessive fiber optic power loss.
To overcome the problem of conventional OAD systems having optical jumpers with high insertion loss, and inconvenience associated with a plurality of fiber optic cables protruding from a typical OAD, fiber optic jumpers may be utilized. Low optic loss can be achieved by mechanically positioning the jumper at a 1 inch pitch rather than the standard duplex xc2xd inch pitch, which commonly found in the art. Additionally, low optic loss can be achieved by controlling the fiber loop radius. The physical presence of a fiber optic jumper in an optical add/drop device allows for connection of two fiber optic system common wavelength fibers. The fiber optic jumper of the invention has a casing. A first end of an optical fiber and a second end of the optical fiber extend out of a connector end of the casing. The retraction of the jumper from the OAD exposes fiber optic connections in the OAD and enables a system reconfiguration such as adding or dropping of common wavelengths into open fiber connections. An installed fully bi-directional jumper redirects light within an optical transport system. A bi-directional jumper allows for an additional layer of fiber optic network monitoring intelligence to what is commonly a passive fiber optic transport system.
An installed presence detection function to provide electrical network system intelligence is also desirable for OAD systems. One embodiment of a presence detection device is a physical switch, which is either active or passive and which is activated upon insertion of the jumper. Several types of presence switches may be used including: 1) a silicone pushbutton utilizing a conductive pad; 2) a metal or polyester dome switch construction; 3) an infrared transmitter and receiver; 4) a magneto-resistive device, such as a magnetic Hall effect sensor; or other types of presences switches. In one embodiment, a magnet is provided in the chassis of the jumper to engage a Hall effect sensor feature contained on the OAD product chassis to facilitate monitoring of the insertion or withdrawal of the fiber channel jumper. The magnetic Hall effect sensor is preferred because the components may be designed as a sealed construction non tactile interface, which greatly increases the reliability of the presence switch.